Edge oriented block motion estimation for video coding

Chan, Yui-Lam; Siu, Wan-Chi

doi:10.1049/ip-vis:19971199

Cited by 34 publications

(25 citation statements)

References 13 publications

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“…From Table VII, it can be seen that the PSNR performance of DA+MCDCT+UMC is better than that of the DA+MCDCT+UMA. This result is not unexpected since not all the motion vectors obey (17). For video sequences with low motion activities, (17) is satisfied for most macroblocks.…”

Section: Resultsmentioning

confidence: 73%

“…This is done by assuming that motion activities between pictures are uniform [uniform motion assumption (UMA)], such that, (17) Hence, (8) can be further simplified as (18) In order to achieve high video quality for transcoding and low computational complexity, this assumption has to be verified. A process, designated as uniform motion checking (UMC), is applied to check the validity of (17). If the motion activities between pictures cannot fulfill this requirement, will be switched to position to estimate the new DCT coefficients using (8) instead of (18) (see Fig.…”

Section: Fast Transcoding Of the B Frame Using A Uniform Motion Asmentioning

confidence: 99%

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On Transcoding a B-Frame to a P-Frame in the Compressed Domain

Siu

Chan

Fung

2007

IEEE Trans. Multimedia

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Abstract-Only a limited number of methods have been proposed to realize heterogeneous transcoding, for example from MPEG-2 to H.263, or from H.264 to H.263. The major difficulties of transcoding a B-picture to a P-picture are that the incoming discrete cosine transform (DCT) coefficients of the B-frame are prediction errors arising from both forward and backward predictions, whilst the prediction errors in the DCT domain arising from the prediction using the previous frame alone are not available. The required new prediction errors need to be re-estimated in the pixel domain. This process involves highly complex computation and introduces re-encoding errors. We propose a new approach to convert a B-picture into a P-picture by making use of some properties of motion compensation in the DCT domain and the direct addition of DCT coefficients. We derive a set of equations and formulate the problem of how to obtain the DCT coefficients. One difficulty is that the last P-frame inside a GOP with an IBBP structure, for example, needs to be transcoded to become the last P-frame in the IPPP structure, and it has to be linked to the previous reconstructed P-frame instead of to the I-frame. We increased the speed of the transcoding process by making use of the motion activity which is expressed in terms of the correlation between pictures. The whole transcoding process is done in the transform domain, hence re-encoding errors are completely avoided. Results from our experimental work show that the proposed video transcoder not only achieves a speed-up of two to six times that of the conventional video transcoder, but it also substantially improves the quality of the video.Index Terms-B-picture and P-picture, compressed domain processing, heterogeneous transcoding, video coding and transcoding.

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Section: Resultsmentioning

confidence: 73%

Section: Fast Transcoding Of the B Frame Using A Uniform Motion Asmentioning

confidence: 99%

On Transcoding a B-Frame to a P-Frame in the Compressed Domain

Siu

Chan

Fung

2007

IEEE Trans. Multimedia

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“…其次,以宏块为单位进行运动估计,如果同一个宏块中包含两个或两个以上具有不同运动形式的物体,或者在一个边界宏块中,如果对象的前景被较强的背景所影响,那么经过运动补偿后,就会不可避免地产生不连续的物体边界,以致影响运动补偿的视觉效果 [7] .…”

Section: 平面对象包围盒内部的宏块可被划分为外部宏块(Transparent Macroblock)、内部宏块(opaque Munclassified

Binary Alpha-Plane Assisted Fast Motion Estimation Scheme of Video Object

Song¹,

Wang²,

Zhang³

2010

Journal of Software

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This paper proposes a fast motion estimation scheme of arbitrarily shaped video object. The instructive role of the alpha-plane taking part in the motion estimation of video object is discussed, and a weighted binary alpha-plane matching criterion (WBAMC) is proposed by using boundary extension and boundary mask techniques.Based on priority search strategy, this paper proposes a fast binary alpha-plane assisted motion estimation (BAAME) scheme of video object. First, the BAAME uses alpha-plane and the WBAMC criterion to limit the search of boundary macro-blocks (MBs) into small unimodal area of two starting points so that a conventional fast motion estimation algorithm can be employed to search the motion vectors (MVs) of boundary MBs. Second, the BAAME predicts the starting points of opaque MBs by using MVs of neighboring boundary MBs and then employs a fast motion estimation algorithm to compute the MVs of opaque MBs. The proposed scheme can be combined with many spatial domain based and frequency domain based different motion estimation algorithms, and be effectively applied to object-based video codecs. The experimental results show that the BAAME scheme can always reach high motion estimation accuracy and better subjective quality for standard test video sequences which have different characteristics respectively. The proposed scheme can achieve 0.1~0.8dB higher prediction quality on average than DS (diamond search) and PSA (priority search algorithm) (BAAS (binary alpha-plane assisted search)+DS), and a *

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“…Motion estimation and compensation [1,2] is one of the most important techniques to enable video coders to achieve a high ratio compression. The efficiency of this approach depends greatly on the accuracy of the motion estimation which can efficiently explore the inter-frame redundant information.…”

Section: Introductionmentioning

confidence: 99%